A diesel engine is generally used in trains, vessels, construction equipment or the like, and the use of such a diesel engine is becoming increasingly common due to serious introduction of diesel sedans.
The increased use of the diesel engine causes the emission of particulate matter (PM) contained in exhaust gas discharged from the diesel engine to increase. The particulate matter is a primary cause of environmental pollution, in particular, air pollution, and if it is sucked in lungs or respiratory organ of a human body, it causes fatal damage to the human body. Therefore, it tightens regulations on the emission of the particulate matter all over the world.
In order to address the above problem such as environmental pollution, a diesel particulate filter (DPF) for collecting and processing the particulate matter to prevent discharge of the particulate matter from the diesel engine to the atmosphere has been developed. With the diesel particulate filter for the diesel engine, if it reaches a predetermined time after the particulate matter is collected by the filter, the filter is regenerated by repeating a process of combusting the filtered exhaust gas or getting the particulate matter off the filter. In case of the latter, if the particulate matter is deposited onto an interior wall of the filter, the particulate matter is likely to be hardened, and thus the particulate matter is not easily got off the filter. In addition, the performance of the filter is deteriorated by the particulate matter remaining on the filter. For this reason, as the former, most of the diesel particulate filters collect the particulate matter and forcibly burn it by using an electric heater or burner.
FIG. 1 is a cross-sectional view of an engine room 7 equipped with a diesel particulate filter 6 of a related art. Referring to FIG. 1, the exhaust gas emitted from the diesel engine 5 passes through a diesel particulate filter 6, and is then discharged to a tail pipe 1.
However, since the diesel particulate filter 6 forcibly burns the particulate matter by using the electric heater or burner at the time of regenerating the filter, gas of very high temperature, for example, the highest 1000° C., is discharged through the tail pipe 1. Injury of a human body of fire may be caused by the overheated gas.
In addition, since the tail pipe 1 is heated by the overheated gas, the person may suffer burn even by contacting the tail pipe 1, even though directly coming in contact with the overheated gas.
Moreover, if the overheated gas discharged through the tail pipe 1 flows backward into the engine room 7, the durability of various components and electric wiring in the engine room is deteriorated.